In many European cities, you can just walk to a grocery store a few blocks away, and just go every day or two, picking up a few items each time.
You only need one bag, so it’s not a burden at all. Worst case, it’s incredibly easy to add a basket to a bike (or mobility scooter), so you can put your day’s groceries in there.
And as an added benefit of density, grocery stores are more efficient. There is a “general” one with all of the basics — fruit and veggies, cereal, meat, pasta, basic sauces, breads, convenience foods. Those are everywhere. Then if you go a little further, you’ll find specialty stores with “asian foods” or others, which you may not use as often but can get some rarer things there.
In my experience, having done both, it is a bit more time efficient at the Costco, but it also changes what you buy (lots of fresh food doesn't actually do well for two weeks). This is assuming you have the places you need in easy walking distance of course. At one time I had a grocer/butcher/wine shop/etc. all literally on the way I would walk home from subway anyhow, so my overall time was probably even shorter than a big grocery run every 2 weeks. I paid a bit more, but then I got better produce and bread, and could change meal planning on a dime if I saw something good. All tradeoffs I guess.
You only need one bag, so it’s not a burden at all. Worst case, it’s incredibly easy to add a basket to a bike (or mobility scooter), so you can put your day’s groceries in there.
And as an added benefit of density, grocery stores are more efficient. There is a “general” one with all of the basics — fruit and veggies, cereal, meat, pasta, basic sauces, breads, convenience foods. Those are everywhere. Then if you go a little further, you’ll find specialty stores with “asian foods” or others, which you may not use as often but can get some rarer things there.